Certain pool jet fittings are configured to direct filtered water downward or downward at an angle. For example, some devices such as the Paramount DownJet, is a fixed orifice/fixed angle eyeball style return nozzle that directs the stream perpendicular from the water inlet pipe, along the pool wall and continuing onto the pool floor, in order to sweep dirt and debris from the pool walls and pool floor. Another type of right angle nozzle is the Paramount SwingJet, which is a fixed orifice/variable angle down jet that automatically rotates during cycling. Another type of down jet is the Venturi return from Infusion Pool products, also a fixed orifice/fixed angle nozzle.
With the advent of energy saving two-speed and variable speed pool pumps that save energy by running at lower speeds, there exists a need to optimize flow patterns for best performance and pump efficiency, saving energy and therefore saving money for the pool owner. Pool pumps typically are operated several hours of the day at high speeds, and consume a large amount of energy. The energy consumption involved during such usage can account for a major portion of a home owner's energy costs. To address this problem, variable speed water pumps have been introduced that can operate at low speeds. When operating at low speeds, however, the pool jet fittings do not perform their functions adequately. The aforementioned devices, with the exception of the Paramount SwingJet, being of the fixed orifice design lack the capability to tune the orifice size for optimal flow and pump efficiency. The SwingJet does have provisions to accept different sized fixed orifices, but changing size during setup is difficult, and would never be considered by the pool owner to accommodate the various pump speeds necessary to facilitate all situations.
One drawback of any multi-part device in these applications, such as the Paramount SwingJet, is the possibility of sticking or jamming due to debris and/or abrasives getting into the mechanisms.